Inducible NOS and PAI-1 were significantly higher in patients MetSy compared to the control group, regardless of the obesity status, with iNOS being significantly higher in obese patients with MetSy compared to non-obese subjects with MetSy (115.93 ± 33.19 vs. 130.10 ± 35.84, p < 0.01). This evidence concerns the gene NOS2 and obesity due to melanocortin 4 receptor deficiency.